Iontophoresis and Active Dental Appliances
Dental trays, toothbrushes, and other devices are provided for the active delivery of medicaments into hard and soft tissues, particularly those of the oral cavity. The devices apply an AC voltage with a DC offset to drive medicaments into the tissues.
This application claims the benefit of U.S. Provisional Application No. 60/902,001 filed on Feb. 16, 2007 and entitled “Iontophoresis and Active Dental Appliances” which is incorporated herein by reference. This application also cites Disclosure Document No. 570858 filed on Feb. 16, 2005 as a request that the Disclosure Document be retained.
BACKGROUND OF THE INVENTION1. Field of the Invention
The present invention relates generally to dentistry and more specifically to active administration of medicaments to hard and soft tissues.
2. Description of the Prior Art
It is a common dental practice to deliver medicaments to the dental arch and tissues of the oral cavity using a dental tray containing a desired medicament. For example, a sodium fluoride (NaF) gel is dispensed into a disposable dental tray and placed over the dental arch to remineralize the teeth and help prevent tooth decay. In some cases, a dentist will fabricate a custom dental tray specific to the patient's dental arch and teeth, while in other instances medicaments such as tooth whiteners are provided in individually packaged disposable universal dental trays. Similarly, medicaments are provided on a strip that is placed over the teeth of the dental arch to whiten teeth, for example. All of the aforementioned methods of medicament delivery are examples of passive delivery to the target site in the oral cavity. That is, the medicament is placed in direct contact with the target site and any penetration into the target site is achieved by diffusion down a concentration gradient and is limited by the permeability of the target site to the medicament.
There are a number of issues associated with the passive delivery a medicament into the dental pulp. Some medicaments such as antibiotics, glucocorticoids and nonsteroidal anti-inflammatory drugs (NSAIDs) may save the pulp in the boundary zone between reversible and irreversible pulpitis, however, when a medicament is topically applied (passive delivery) to dentin, the drug diffusion into the pulp is inhibited by an outward flow of dentinal fluid. Additionally, dentin sclerosis or reparative dentin formation following physiological or pathological stimulation results in a reduction of dentin permeability and appears to influence the drug diffusion through dentinal tubules. Even if the drugs reach the pulpal tissue, odontoblasts and pulpal microcirculation may prevent the drugs from reaching an effective concentration.
By contrast, active delivery employs a driving force to drive the medicament into the target site. Reports in the professional dental literature, for example, describe the use of iontophoresis to deliver various medicaments to the dental arch and intraoral soft tissues. Iontophoresis employs an electric field to drive ions of soluble salts into the target site. Iontophoresis has been used in dentistry to delivery a variety of ionizable medicaments including fluorides, desensitizers, steroids, anesthetics, and other drugs. Because of the anatomy of the oral cavity and of the target site (e.g., one or more teeth), a dental tray delivery configuration is often employed. Here, the tray includes a medicament and is placed over the tooth or teeth. A voltage is maintained between the tray and the target site to produce the electric field that drives ions from a medicament into enamel, dentin, and exposed cementum. A patch device that operates according to similar principles has also been used to actively delivery medicaments to soft tissues in the mouth.
With conventional iontophoresis, a power supply is used to apply a constant current, such that the flow of electrons translates into an ion flux across the oral mucosa, teeth, cementum, or dentin. It will be appreciated that components within the medicament that are not ionized will not be influenced by the electric field and different ions subject to the electric field will have different mobilities based on factors such as their charge and mass. For analytes that are bound to proteins, for instance, only the free fraction can significantly contribute to charge transport across the mucosa. In short, iontophoresis works well to deliver ions that are small, highly charged, present in high concentration, and not significantly protein-bound.
As one example, a dental tray has been used to deliver fluoride to the teeth, here, a sponge soaked with NaF is placed in a dental tray having an electrode disposed in the bottom of the dental tray. Another electrode is attached to the patient's body. The NaF dissociates into Na+ and F− ions and under the influence of the electric field the F− ions are driven away from the negatively charged tray electrode and towards and into the positively charged tooth or teeth. The DC field can be varied to improve ion mobility.
The prior art also includes a two-step ion exchange method wherein a first pre-treatment dental tray containing a metal salt solution is delivered to the teeth of the dental arch and removed after several minutes. Then, in a second step, an electrically active dental tray containing a fluoride solution is delivered to the dental arch. Electrical contacts are located on the facial surface of the electrically active dental tray, and when a voltage is applied, the electric field causes an ion exchange in the teeth such that fluoride ions are exchanged with hydroxyl ions in the enamel. This process, however, is an ion exchange process rather than iontophoresis by definition.
SUMMARYAn exemplary system for delivering a medicament into hard or soft tissue comprises a conductive layer and a dielectric layer disposed over the conductive layer. The system also comprises an electrode and a power supply configured to apply AC with a DC offset between the conductive layer and the electrode. In some embodiments the conductive layer is patterned. The dielectric layer including openings, which in some embodiments result from the dielectric layer being patterned with the openings. One suitable material for a patterned dielectric layer is fluorinated ethylene-propylene. In other embodiments the dielectric layer comprises a hydrogel. In these embodiments the openings therein are pores or channels in the hydrogel. The electrode can comprise a metal strip or conductive adhesive patch in various embodiments. The power supply can comprise a battery.
In some embodiments, the system further comprises a dielectric substrate wherein the conductive layer is disposed between the dielectric substrate and the dielectric layer. In some of these embodiments the dielectric substrate comprises polyimide. Also in some of these embodiments the dielectric substrate comprises a dental tray. Other embodiments of the system comprise a toothbrush, where a bristle of the toothbrush comprises the conductive and dielectric layers. Still other embodiments of the system comprise an endo fie that comprises the conductive and dielectric layers.
An exemplary dental tray comprises a dielectric substrate formed to have a trough and to approximate the curvature of a dental arch, a dielectric layer conforming to the dielectric substrate and including openings, and a conductive layer disposed between the dielectric substrate and the dielectric layer. The exemplary dental tray can comprise, in some embodiments, a medicament disposed within the trough. The exemplary dental tray can also comprise a power supply configured to generate AC with a DC offset. In some of these embodiments, the power supply includes a battery. In various embodiments of the dental tray the conductive layer comprises a pattern, the dielectric layer comprises a pattern of openings, or the dielectric layer comprises a hydrogel.
An exemplary toothbrush comprises a conductive pad disposed on an exterior surface, a plurality of conductive bristles each including an electrically conductive core surrounded by a patterned dielectric layer, a battery, and a control circuit in electrical communication with the battery, the conductive pad, and the plurality of conductive bristles and configured to apply a voltage between the conductive pad and the conductive bristles. The control circuit of the toothbrush can be configured to apply DC between the conductive pad and the conductive bristles, or apply AC with a DC offset between the conductive pad and the conductive bristles.
An exemplary method for delivering a medicament into tissue comprises placing the medicament between the tissue and a conductive layer of a device and applying AC with a DC offset between the tissue and the conductive layer. In some embodiments applying AC with a DC offset between the tissue and the conductive layer includes attaching an electrode to the person being treated. Applying AC with a DC offset between the tissue and the conductive layer can include applying about 300 to 1500 mA/cm2. Applying AC with a DC offset between the tissue and the conductive layer can also include applying DC current of about 0.2 mA and/or applying AC current of about 0.05 mA.
In some instances the device comprises a dental tray and placing the medicament between the tissue and the conductive layer includes placing the dental tray over a dental arch. Some of these embodiments further comprise filling a trough of the dental tray with the medicament. In other such embodiments, the dental tray includes a hydrogel layer disposed over the conductive layer and including the medicament. In other embodiments of the method, the device comprises a toothbrush and the method further comprises applying a toothpaste including the medicament to the toothbrush. The device can also comprise an endofile, the medicament comprises an agent to block nerve conduction, and the method further comprises applying the agent to a tooth.
The present disclosure is directed to the active delivery of medicaments into hard and soft tissues, particularly those of the oral cavity. Iontophoresis is employed to drive medicaments into the tissues using a DC voltage. An AC voltage can be added to the DC voltage to improve the mobility of the medicaments through the tissues. Devices for the active delivery of medicaments into hard and soft tissues are also provided, as well as methods for their use, and methods for their manufacture.
Attention is first directed to an exemplary device for the active delivery of medicaments.
In the example illustrated by
The conductive layer 105 can also be prepared through other methods. For example, a suspension of conductive metal particles in a conductive liquid binder, like a conductive ink, can be applied to the substrate 100, for example, using ink jet or other standard printing technologies, for example transfer printing technologies such as pad printing. Preferably, the suspension dries rapidly once it is applied to the substrate 100. Such printing techniques allow the conductive layer 105 to be patterned as described above.
The conductive layer 105 pattern can be non-linear, for example it can be in the form of a wave or zig-zag pattern. Patterning the conductive layer 105 in this fashion allows the substrate 100 to be deformed to a greater extent during a subsequent molding process, described below, without breaking the conductive layer 105 pattern. The conductive layer 105 pattern can be designed such that the pattern becomes linear or nearly linear, after deformation of the substrate 100 during the molding process.
Also not shown in
To form the substrate 100 into the shape of a dental tray, the substrate 100 with the conductive layer 105 and patterned dielectric layer is first folded to form a trough, as shown in
Alternatively, the substrate 100 can be molded into the final shape before other layers are added, for example through electroplating, vapor deposition and/or sputtering. In still other embodiments, the substrate 100 is molded after the conductive layer 105 has been provided as a continuous layer, but before the conductive layer 105 has been patterned. To pattern the conductive layer 105 after the substrate 100 has been molded, a process similar to pad printing can be employed. Here, an appropriate masking material is patterned in the form of the desired conductive layer 105 pattern onto a flexible mandrel that nearly matches the shape of the cavity of the molded substrate 100, for example a silicone mandrel. The mandrel is then inserted into the formed substrate 100 and pressed against the surface thereby transferring the masking material to the substrate 100. A standard etching process is then used to remove any conductive material 105 not protected by the masking material. Similarly, this masking technique can be used to form a mask directly on the substrate 100, and then a solution or suspension comprising a conductive material can be applied over the mask to form the patterned conductive layer 105.
In certain embodiments the geometry of the molded substrate 100 allows the conductive solution or suspension to be transferred from a roller, for example a silicone roller. In some of these embodiments, the conductive solution or suspension is applied to a surface of the roller away from the surface where the roller contacts the substrate 100 as the roller is moved along the substrate 100. This allows for the use of a roller small enough to fit into the molded geometry of the substrate and to apply a continuous pattern of the conductive layer 105 much longer than the circumference of the roller. In some of these embodiments, a raised pattern on the surface of the roller (or the surface of the flexible mandrel described above) can be coated with the conductive solution or suspension to transfer the pattern onto the substrate 100.
The dielectric layer 310, as noted above, serves to keep the conductive layer 315 from contacting the tissue to be treated, preventing a direct electrical short. In various embodiments, the thickness of the dielectric layer 310 is about 3 mm, about 2 mm, about 1 mm, or about 0.5 mm to provide approximately that spacing between the conductive layer 315 and the tissue being treated. The dielectric layer 310 can comprise, for example, a layer of fluorinated ethylene-propylene (FEP). In some embodiments, the dielectric layer 310 is patterned with openings through which the conductive layer 315 is exposed. Referring again to
In certain embodiments, the dielectric layer 310 comprises a hydrogel layer. The hydrogel layer can be bonded, such as by lamination, to the conductive layer 315, though it will be appreciated that the dielectric layer 310 does not have to be firmly attached to the conductive layer 315 and in some embodiments is held in place merely by van der Waals or other weak forces, or is removable. In some instances, no heat or pressure need be applied to bond the hydrogel to the conductive layer due to the inherent tackiness of the hydrogel. The hydrogel layer can include, for example, a concentration of a medicament such as a whitening agent. Hydrogels such as PVA and p-HEMA with or without the medicament can also be bonded to the conductive layer 315. In contrast to the previous embodiments, since the hydrogel layer inherently includes openings in the form of channels or pores, the hydrogel layer does not have to be patterned to include openings.
In still other embodiments the outer dielectric layer 305 can be patterned with holes to increase the rate and ease of fluid movement, for example saliva, through the dental tray 300 and into the treatment area. This fluid movement can increase the rate at which the hydrogel swells and therefore the rate at which the medicament can move from the hydrogel into the target tissue. Alternatively, the outer dielectric layer 305 can be constructed of a porous material that allows the free movement of fluid, for example saliva, through the outer dielectric layer 305 and in to the treatment area.
Examples of medicants include tooth whiteners such as hydrogen peroxide, agents to treat dental sensitivity such as potassium nitrate and particulate bioglass such as Novamin® (calcium sodium phosphosilicate), glucocorticoids, antimicrobial agents such as antibiotics, antiviral agents, agents to remineralize teeth such as Novamin® and fluorides like sodium fluoride, sodium fluoride aqueous solution, potassium fluoride, and potassium fluoride aqueous solution, anti-inflammatory agents such as steroids, nitrates like potassium nitrate in aqueous solution, agents to block nerve conduction such as lidocaine and other topical anesthetics, and anti-inflammatory agents such as nonsteroidal anti-inflammatory drugs (NSAIDs) like naproxen and ibuprofen. Liposomes as drug or medicament carriers can also be used which offers the advantage of using poorly soluble drugs in combination with iontophoresis. More specific examples of fluoride medicaments include a gel of acidulated phosphate fluoride (11.23% [12,300 ppm] fluoride), a gel or a foam of sodium fluoride (0.9% [9,040 ppm] fluoride), a gel of sodium fluoride (0.5% [5,000 ppm] fluoride), and a gel of stannous fluoride (0.15% [1,000 ppm] fluoride).
A power supply 410 is configured to apply an appropriate current and voltage between the conductive layer 315 of the dental tray 300 and an electrode 415 in electrical contact with the person being treated. In some embodiments, the electrode 415 is in contact with the person's hand, for example. In the example shown in
The power supply 410 can apply DC, AC, or AC with a DC offset. In exemplary embodiments, a suitable ratio of the current relative to the conductive area of the electrode 415 is within a range of about 300 to 1500 mA/cm2. In some of these embodiments the ratio is within a range of about 800 to 1200 mA/cm2. In still further of these embodiments the ratio is about 500 mA/cm2 or 1000 mA/cm2. In various embodiments that employ AC, with or without a DC offset, a suitable frequency lies in the range of about 0.1 Hz to 1,000,000 Hz, for example 100,000 Hz. Suitable treatment times, in some embodiments, range from about 0.1 to about 60 minutes, but can also be in the range of about 1 to 30 minutes, or about 1 to 5 minutes.
The power supply 410 can be palm-sized in some embodiments. The power supply 410 can also comprise a microprocessor and be programmable, allowing a user to customize protocols. In some embodiments, the power supply 410 is configured to sense current, voltage, and resistance when coupled to the person being treated. For example, during constant current iontophoresis, when resistance increases due to polarization or a decrease in the number of available ions to conduct charge, the power supply 410 can respond by increasing the voltage to maintain the constant current through the oral tissues.
The power supply 410 shown in
The power supply 410 in
With particular reference to
The power supply 410 may apply DC, AC, or AC with a DC offset. Examples of some suitable waveforms are shown in
Although the DC offset in both of
The use of various AC waveforms to temporarily affect the porosity of biological materials is a technique sometimes referred to as electroporation. Tissues are porous strictures consisting of various material phases (e.g., cells, fibrous tissue, and minerals) with a charged perfusant. The porosity or effective pore size of some tissues can be increased by using high voltage pulses. Using such waveforms as described above can enhance delivery of medicaments via ion pumping, for instance. As one example, electroporation reversibly makes certain lipid bilayers more permeable by creating aqueous pores. From a bulk tissue perspective, using a pulsed or an AC waveform can effectively increase the mobility of a particular charged entity through the tissue.
A further advantage derived from electroporation and electric fields in general, as used herein, derives from the increased fluid flow or mass flow that occurs when certain tissues are subjected to various electrics fields. For example, gingival tissues, and in particular intra-pocket gingival tissues when subjected to electric fields and electroporation can be stimulated to produce increased gingival crevicular fluid flow or mass flow. Gingival crevicular fluid flows generally from the periodontal pocket into the oral cavity and fluids from the oral cavity can flow into the periodontal pocket. For the purposes of delivering a medicament into a periodontal pocket, the devices described herein induce bulk fluid flow or mass flow to increase from the periodontal pocket to the oral cavity simultaneous with the flow of medicament ions (mass flow) from such devices into the periodontal pocket. The net result is increased fluid (mass) and ion flow in both directions. Thus, by virtue of increasing the bi-directional fluid flow via the induced electric field and electroporation, improved delivery of medicaments into periodontal pockets is achieved.
Three specific examples of the use of the dental tray 300 will now be provided with reference to
A second example is directed to the use of iontophoresis to effectively deliver potassium ions to nerve cells. In this example, a medicament comprising a viscous 5% potassium nitrate gel is prepared at a pH of about 7.0. The gel is dispensed into the trough of the dental tray 300 and placed over the patient's dental arch. The conductive layer 315 (or the first portion 600 thereof in
In a third example, a paste including Novamin® is dispensed into the trough of the dental tray 300 and the dental tray is applied as described in the prior two examples. The iontophoresis serves to accelerate the rate of calcium hydroxyapatite deposition to more rapidly occlude pores in tooth enamel. This, in turn, can lead to a more rapid decrease in sensitivity.
Like the full dental tray 300, another embodiment directed to a half-tray or strip appliance can also be used. For example, the strip appliance can comprise a dental tray that covers essential just the facial surfaces of the teeth. The strip appliance, like the dental tray 300, can be flexible and comprise an outer dielectric layer 305, an inner dielectric layer 310, and a conductive layer 315 disposed between the outer and inner dielectric layers 305 and 310. As above, the dielectric layer 310 can be patterned or can comprise a hydrogel. For fluoride treatment, in those embodiments in which the dielectric layer 310 does not comprise a hydrogel, a NaF gel is dispensed on the dielectric layer 310 and formed to the facial surfaces of the teeth. Alternatively, the dielectric layer 310 can be a hydrogel comprising NaF or a foam layer comprising a liquid or gel comprising NaF. Operation of the strip appliance can be the same as described above with respect to the dental tray 300. In further embodiments, the strip appliance can include the complete outer dielectric layer 305 of the full dental tray 300 but the inner patterned dielectric layer 310 and the conductive layer 315 are disposed on only one surface, for example, the facial surface of the dental tray.
In still other embodiments, the dielectric layer 1120 is porous. The porosity in these embodiments can be filled with a medicament or a hydrogel including the medicament. Here, the brush may be used for a single application of the medicament before being discarded. In such embodiments the brush is pre-loaded to deliver a pre-measured amount of the medicament. In addition to such single-use disposable toothbrushes 1000, some embodiments are directed to short duration use where the amount of medicament is sufficient to last for 5 days or a week, for example.
The toothbrush 1000 functions in a manner similar to the dental tray 300 described above. A medicament is applied to the bristles of the toothbrush 1000, in the form of a toothpaste for example, and brushed against the teeth. The voltage applied by the control circuit 1010 between the user and the conductive bristles 1015 serves to drive the medicament into the teeth. All of the various waveforms and ranges for voltage and current described above with respect to the dental tray 300 are also applicable to the toothbrush 1000.
In various embodiments the toothbrush 1000 is designed to be used with a specific medicament and the control circuit 1010 is Configured to apply a single preset configuration comprising the appropriate polarity, voltage, current, DC offset, etc. Some of these embodiments are directed to single-use or short duration use toothbrushes 1000 described above. In other embodiments, the user can change the settings of the control circuit 1010 to allow for the application of different medicaments. In further embodiments, the power supply (e.g., power supply 410) is external to the toothbrush 1000 and is electrically coupled between the toothbrush 1000 and an electrode (e.g., electrode 415) adhered to the user.
One suitable device for use in the method 1400 is a dental tray, such as dental tray 300, or a strip appliance described above. In these embodiments, step 1410 can comprise placing the dental tray or strip appliance over a dental arch. Where the dielectric layer 310 of the dental tray or strip appliance comprises a patterned material, step 1410 can also comprise filling a trough of the dental tray or strip appliance with the medicament before placing the dental tray or strip appliance over the dental arch.
Another suitable device for use in the method 1400 is a toothbrush, such as toothbrush 1000 described above. In these embodiments, step 1410 can comprise applying a toothpaste including the medicament to the toothbrush and then brushing the teeth with the toothbrush. Yet another suitable device for use in the method 1400 is an endofile, such as the endofile 1300 described above. Here, the medicament can comprise an agent to block nerve conduction, for instance, and step 1410 can comprise applying the agent to a tooth.
For any of the devices described herein, where the dielectric layer 310 includes a hydrogel, the hydrogel may not include the medicament at the time of manufacture. Instead, the medicament is applied to the hydrogel shortly before the device is to be used. The medicament can be sprayed onto the hydrogel surface, or the device can be immersed into a solution comprising the medicament for a predetermined length of time. In this way, shortly before use, the hydrogel takes up the medicament. These embodiments can be advantageous where the medicament may not have a long shelf-life, for example.
For various devices, the step 1420 can include attaching an electrode to the person being treated. The step 1420 can also include applying about 300 to 1500 mA/cm2 in some embodiments. In various embodiments, step 1420 includes applying DC current of about 0.2 mA or applying AC current of about 0.05 mA.
In the foregoing specification, the present invention is described with reference to specific embodiments thereof, but those skilled in the art will recognize that the present invention is not limited thereto. Various features and aspects of the above-described present invention may be used individually or jointly. Further, the present invention can be utilized in any number of environments and applications beyond those described herein without departing from the broader spirit and scope of the specification. The specification and drawings are, accordingly, to be regarded as illustrative rather than restrictive. It will be recognized that the terms “comprising,” “including,” and “having,” as used herein, are specifically intended to be read as open-ended terms of art.
Claims
1. A system comprising:
- a conductive layer;
- a dielectric layer disposed over the conductive layer, the dielectric layer including openings;
- an electrode; and
- a power supply configured to apply AC with a DC offset between the conductive layer and the electrode.
2. The system of claim 1 wherein the conductive layer is patterned.
3. The system of claim 1 wherein the electrode includes a metal strip.
4. The system of claim 1 wherein the electrode includes a conductive adhesive patch.
5. The system of claim 1 wherein the power supply comprises a battery.
6. The system of claim 1 further comprising a dielectric substrate wherein the conductive layer is disposed between the dielectric substrate and the dielectric layer.
7. The system of claim 6 wherein the dielectric substrate comprises polyimide.
8. The system of claim 6 wherein the dielectric substrate comprises a dental tray.
9. The system of claim 1 further comprising a toothbrush, wherein a bristle of the toothbrush comprises the conductive and dielectric layers.
10. The system of claim 1 wherein an endo fie comprises the conductive and dielectric layers.
11. The system of claim 1 wherein the dielectric layer comprises a hydrogel.
12. The system of claim 1 wherein the dielectric layer comprises a foam.
13. The system of claim 1 wherein the dielectric layer comprises fluorinated ethylene-propylene patterned with openings.
14. A dental tray comprising:
- a dielectric substrate formed to have a trough and to approximate the curvature of a dental arch;
- a dielectric layer conforming to the dielectric substrate and including openings; and
- a conductive layer disposed between the dielectric substrate and the dielectric layer.
15. The dental tray of claim 14 further comprising a medicament disposed within the trough.
16. The dental tray of claim 14 further comprising a power supply configured to generate AC with a DC offset.
17. The dental tray of claim 16 wherein the power supply includes a battery.
18. The dental tray of claim 14 wherein the dielectric layer comprises a hydrogel.
19. The dental tray of claim 14 wherein the dielectric layer comprises a pattern of openings.
20. The dental tray of claim 14 wherein the conductive layer comprises a pattern.
21. A toothbrush comprising:
- a conductive pad disposed on an exterior surface;
- a plurality of conductive bristles each including an electrically conductive core surrounded by a patterned dielectric layer;
- a battery;
- a control circuit in electrical communication with the battery, the conductive pad, and the plurality of conductive bristles and configured to apply a voltage between the conductive pad and the conductive bristles.
22. The toothbrush of claim 21 wherein the control circuit is configured to apply DC between the conductive pad and the conductive bristles.
23. The toothbrush of claim 21 wherein the control circuit is configured to apply AC with a DC offset between the conductive pad and the conductive bristles.
24. A method for delivering a medicament into tissue, the method comprising:
- placing the medicament between the tissue and a conductive layer of a device; and
- applying AC with a DC offset between the tissue and the conductive layer.
25. The method of claim 24 wherein the device comprises a dental tray and placing the medicament between the tissue and the conductive layer includes placing the dental tray over a dental arch.
26. The method of claim 25 further comprising filling a trough of the dental tray with the medicament.
27. The method of claim 25 wherein the dental tray includes a hydrogel layer disposed over the conductive layer and including the medicament.
28. The method of claim 24 wherein the device comprises a toothbrush and the method further comprises applying a toothpaste including the medicament to the toothbrush.
29. The method of claim 24 wherein the device comprises an endofile, the medicament comprises an agent to block nerve conduction, and the method further comprises applying the agent to a tooth.
30. The method of claim 24 wherein applying AC with a DC offset between the tissue and the conductive layer includes attaching an electrode to the person being treated.
31. The method of claim 24 wherein applying AC with a DC offset between the tissue and the conductive layer includes applying about 300 to 1500 mA/cm2.
32. The method of claim 24 wherein applying AC with a DC offset between the tissue and the conductive layer includes applying DC current of about 0.2 mA.
33. The method of claim 24 wherein applying AC with a DC offset between the tissue and the conductive layer includes applying AC current of about 0.05 mA.
Type: Application
Filed: Feb 19, 2008
Publication Date: Aug 21, 2008
Inventors: Mark G. Fontenot (Palo Alto, CA), Philip R. Houle (Sunnyvale, CA)
Application Number: 12/033,827
International Classification: A61C 19/06 (20060101); H02G 3/00 (20060101); A46B 9/04 (20060101); A61C 17/00 (20060101);